Coating compositions are utilized to form coating layers such as, for example, primer layer, basecoat layer and clearcoat layer, for protective and decorative purposes. These coating compositions can be used in automotive OEM and refinish coating applications and provide a protective layer for the underlying substrate and can also have an aesthetically pleasing value. Presently, automotive coatings are typically multilayer coating systems including a clearcoat layer overlying a basecoat layer, with the basecoat layer overlying one or more additional layers such as a primer layer and an electrocoat layer.
In refinish coating applications, customers desire high productivity and excellent performance. To achieve the productivity desired, coating compositions are preferably able to dry at ambient or slightly elevated temperatures in a relatively short period of time. However, many of today's fast-drying coating compositions do not meet the desired performance requirements, such as excellent stone-chip resistance, humidity resistance, inter- and intra-layer adhesion, and appearance. Further, if the coating layer, such as a basecoat layer has not sufficiently dried prior to subsequent application of a clearcoat composition overlying the basecoat layer to form a clearcoat layer, the application of the topcoat composition will disturb the basecoat layer and the appearance of the basecoat layer will be adversely affected. For example, flake control and metallic appearance (i.e., “downflop”) of basecoat compositions containing special effect pigments, such as metallic and pearlescent flake pigments, will suffer due to disturbance of the flake pigments by intermixing of the basecoat and clearcoat layers at the interface therebetween.
Accordingly, it is desirable to provide coating compositions having a short dry-time and excellent performance. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with this background.